1. Field of the Invention
This invention relates to a vascular introduction device with a lateral arm, this introduction device being destined to be used to insert a catheter into the vascular system.
The introduction device proper is in the shape of a tube which is provided with a non-return valve at its rear or proximal part. The introduction device is, prior to being installed in the blood vessel, slid onto a pointed cylindrical rod disposed so as to protrude from the opposite ends of the introduction device.
This cylindrical rod is exclusively used at the time of installing the introduction device in the blood vessel subsequent to the opening of a hole in the skin of the patient to be treated, which is performed by means of a needle.
The cylindrical rod is relatively rigid and serves to elastically enlarge the passage towards the vessel as it progresses into the latter. The rod thus facilitates the introduction of the introduction device which follows immediately after, thereby producing a successive increase in the diameter of the entire part inserted into the vessel. The rod is then extracted and replaced by a catheter.
To simplify the utilization of the different types of catheterization, a measurement further applied using diameter measurement units F (French) and the introduction devices currently used for coronary or vascular angiometrics generally have a diameter of 8 F. In such an introduction device, a 7 F catheter can be inserted.
The size of the hole and of the passage dilated by the introduction of the introduction device must be as restricted as possible in order to limit bleeding once this operation has been completed and the introduction device removed, this being all the more delicate that the patient has always, prior to the operation, received anticoagulants intended to reduce the risk of thrombosis formation.
The lateral arm of the introduction device, which is usually terminated by a tap with plural channels, further enables the performing of local rinsing by injection of a fluid, thereby neutralizing clots. This arm can also be connected to a force pump to inject drugs into the vessel or to sample off small quantities of blood by aspiration.
The catheter inserted into the vascular system by means of such an introduction device can be e.g. used to take pressure measurement readings in the different cavities of the heart and to appraise the different functionings of the myocardium and valves.
The introduction device according to the invention can be advantageously used to perform an angioplasty in a coronary artery or peripheral artery. This operation is performed by means of a catheter which is provided, at its distal end, with a dilatation bulb that can be inflated to compress atheromatous plates.
2. Description of the Prior Art
Such catheters are disclosed in detail in French patent No. 2,638,364 of the same applicant, this patent corresponding to U.S. patent application No.291,307, now U.S. Pat. No. 5,057,120.
One of the problems associated angioplasty is that, throughout the period of inflation of the dilatation bulb, the blood flow completely interrupted within t he corresponding artery. It is for this reason that techniques have been developed enabling the time of inflation of dilatation bulbs to be increased. To this end, it has thus been proposed to perform blood perfusion beyond the dilatation bulb by using the catheter itself as a perfusion tube.
Throughout this operation, blood is thus forced back, in synchronism with the heart rate of the patient, in the central channel of the catheter to ensure perfusion downstream of this dilatation bulb in order to avoid various undesirable and dangerous phenomena such as electrical modifications, thoracic pain, left ventricular contractility anomalies.
In order to perform such a perfusion, it has hitherto been necessary to make a second hole towards an artery into which a second introduction device is inserted, though this time only to sample off blood which is then reinjected into the patient via the catheter. An external circuit was thus created comprising a pulsatile unit serving as a perfusion pump and which is capable of aspirating the blood coming from the second introduction device, and of forcing it back periodically towards the catheter according to a variable flow rate corresponding to the diastole and systole phases of the patient's heartbeat.
It is obvious that the need to make a second hole to sample off a quantity of blood corresponding to approximately 100 ml/minute is a major drawback that can prove dangerous when one considers that the operation is often performed on a patient already seriously ill.